1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // <string_view>
10 
11 // constexpr const_iterator rend() const;
12 
13 #include <string_view>
14 #include <cassert>
15 #include <cstddef>
16 
17 #include "test_macros.h"
18 
19 template <class S>
20 void
21 test(S s)
22 {
23     const S& cs = s;
24     typename S::reverse_iterator e = s.rend();
25     typename S::const_reverse_iterator ce1 = cs.rend();
26     typename S::const_reverse_iterator ce2 = s.crend();
27 
28     if (s.empty())
29     {
30         assert(  e ==  s.rbegin());
31         assert(ce1 == cs.rbegin());
32         assert(ce2 ==  s.rbegin());
33     }
34     else
35     {
36         assert(  e !=  s.rbegin());
37         assert(ce1 != cs.rbegin());
38         assert(ce2 !=  s.rbegin());
39     }
40 
41     assert(static_cast<std::size_t>(  e -  s.rbegin()) == s.size());
42     assert(static_cast<std::size_t>(ce1 - cs.rbegin()) == cs.size());
43     assert(static_cast<std::size_t>(ce2 - s.crbegin()) == s.size());
44 
45     assert(  e == ce1);
46     assert(  e == ce2);
47     assert(ce1 == ce2);
48 }
49 
50 
51 int main(int, char**)
52 {
53     typedef std::string_view    string_view;
54 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
55     typedef std::u8string_view u8string_view;
56 #endif
57     typedef std::u16string_view u16string_view;
58     typedef std::u32string_view u32string_view;
59     typedef std::wstring_view   wstring_view;
60 
61     test(string_view   ());
62     test(u16string_view());
63     test(u32string_view());
64     test(wstring_view  ());
65     test(string_view   ( "123"));
66     test(wstring_view  (L"123"));
67 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
68     test(u8string_view{u8"123"});
69 #endif
70 #if TEST_STD_VER >= 11
71     test(u16string_view{u"123"});
72     test(u32string_view{U"123"});
73 #endif
74 
75 #if TEST_STD_VER > 14
76     {
77     constexpr string_view       sv { "123", 3 };
78 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
79     constexpr u8string_view u8sv {u8"123", 3 };
80 #endif
81     constexpr u16string_view u16sv {u"123", 3 };
82     constexpr u32string_view u32sv {U"123", 3 };
83     constexpr wstring_view     wsv {L"123", 3 };
84 
85     static_assert (    *--sv.rend() ==    sv[0], "" );
86 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
87     static_assert (  *--u8sv.rend() ==  u8sv[0], "" );
88 #endif
89     static_assert ( *--u16sv.rend() == u16sv[0], "" );
90     static_assert ( *--u32sv.rend() == u32sv[0], "" );
91     static_assert (   *--wsv.rend() ==   wsv[0], "" );
92 
93     static_assert (    *--sv.crend() ==    sv[0], "" );
94 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
95     static_assert (  *--u8sv.crend() ==  u8sv[0], "" );
96 #endif
97     static_assert ( *--u16sv.crend() == u16sv[0], "" );
98     static_assert ( *--u32sv.crend() == u32sv[0], "" );
99     static_assert (   *--wsv.crend() ==   wsv[0], "" );
100     }
101 #endif
102 
103   return 0;
104 }
105